Carburetor



June 17, 19.30. w. A. BRAcKE-r Er AL 1,764,711

' CARBURETQR; I

Filed Aug. 8, 1927 2 Sheets-Sheet l 'June 17, 1930. w. A. BRACKET-r ETAL 1,764,711

cARBUREToR Filed Aug. 8, 1927 2 Sheets-Sheet 2 `associated is started,

Patented June 17, 1930 stares PATENT .o1-'rica f WELLBY ALLENBRAGKETTAND wrLLiAM nnwnnn RICHARD, on EVANSVILLE, INDrANn, assIGNoRs r.rosUNBnAM minerari: MANUFAcrUnINe COMPANY; 0F EVANsvInLn, INDIANA, Aconronnrion or' INDIANA 1 cAnBUnnToia i @rating temperature.y This isfrequently accomplished by choking the supply of air to the carburetor.TheA degree of `vacuum created in the carburetor by reason of 'the op#veration ofthe engine is thus increased, and

theiamount of liquid'fuel that is forced into the mixing chamber by exto'nal atmospheric pressure islilrewise increased. vTl'ierefore, the ratioof the amount of fuel to the amount of air is increased. Y l f l f It isdiilicult to regulatethe fuel mixture `automatically where an internalcombustion engine is automatically controlled. OurAinvention,contemplates the provision of means for accomplishing suchregulation, however, but this regulation is accomplished by vary" ingthe vrate of fuel supply to the carburetor mixing chamber withoutvarying the rate of air supply.'` i y y Y i Y The principal. object ofour invention,

therefore, isl to provide acarburetor comprising means forzuitomatically regulating the ratio of fueland air to be mixed thereinwhen the enginewithV which the carburetor is .i Other objectsand-adyantagesofour inrentioniwill appear from a consideration ofthefollowin detailed description in connection with the accompanyingdrawings, in which: i i, J i

Figure 1 is a top'plan view of a carburetor embodying my invention; i I,1 Fig. 2 is av Vvertical sectional View` taken along the line H-HofFig. 1; i i, i Fig. 3 is an enlarged fragmentaryview in .perspectiveshowing the construction of a float stemutilized l in thecarburetorvenibodyf ingmyinvention; i i

partly in section, taken along the line IVhIV of Fig. 1;

. Fig.` 5 is a horizontal sectional View taken along the line V--V ofFig. et; and

` Fig. `6 is a fragmentary .sectional view takenY Von a linecorresponding to the line IVe-IV of Fig. 1 and showing one feature of myinvention in modified form. Referring to the drawings, thecarburetorembodying our invention comprises a top portion 5 having a horizontaltubular portion 6 of Venturi form extending'thereacross A reservoirmember 7 of cup form is secured to the top portion 5 by screws 8 andcontains a float 9 that is secured to a vertical stem 10. The stem 10extends"upwardly fin close-tit. ting relation to an opening 11 in adownwardlygextending portion 12 ofthe vtop portion 5. The stem 10 isadapted to be actuated vertically in the opening 11 but is so fittedtherein as to` prevent the` leakage of fuel through said opening aroundthe stem. The opening 11 intersects the Venturi tube 6 kat the centralportion thereof and `is in alignment with a similar opening 13 in theupper wall ofthe tube 6. Anupwardly extending tubularportion 14 ofsaidupper wall is adapted `to receive a screw-threaded stop member 15 thatis provided at the upper end thereof with a lmurled knob 16 whereby thevertical position of thestop member 15 Vmaybe manually adjusted. Avertical pin 17 is secured to the upper wallof the tube G and. engagesthe-periphery of the knobfl Vto prevent accidental .movement of lthestopV` member 15 due to vibration 'o1-other causes. The lower surface ofthe Vstop member 1.5

Y iforms a cavity 18 thatisi adapted to engage the upperextremity of thestem 10 when the same is ac tuatedupwardly through the open- ,AdepressionA 19 forming a cliannelin one side ofthe stem loisadapted toregisterwith an inclined passage 20 in the `downwardly extending portionV12 `of lthe lower wallof the tube 6. The depression 19V is shown in thedrawings as being of rectangular cross-seci-` tion, butrit is obviousthat a channelV of V- Vshaped semicircular or any other desired form ofcross-section may be utilized with equal effectiveness. VThe passageconstitutes a conduit extending downwardly and transversely to the upperextremity of a vertical conduit 21 that is secured to the downwardlyextending portion 12. The conduit 21 extends from this point downwardlythrough an aperture 22 in the float 9 to a point relatively close to thebottoni of the reservoir 7 A fuel conduit is thus provided from a pointnear the bottom of the reservoir7 to the center of the Venturi tube 6,and this conduit is adapted to conduct liquid fuel from the reservoir tothe Venturi tube, as will be hereinafter more fully described.

The channel 19 is tapered downwardly along the stem 10, as shown inFigs. 2 and 3, to provide a conduit extending from the upper-extremityof the passage 20 the center of the Venturi tube 6, this conduit havinga decreasing cross-sectional `areas as the iioat 9 is raised to raisethe stem lO'correspondingly. The position of the vstop member 15 isadapted to be adjusted by the knob :i6 'to limit vertical movement ofthe stem 10, which, therefore, determines the minimum vcross-section ofthe conduit 19 at the pointwhere this conduit is intersected by theconduit 20.

The Venturi tube 6Y is provided at one extremity thereof with a flangeportion 23 that is adapted to be secured tov the intake 'manifold of aninternal combustion engine by cap-screws 24.r A throttle valve 25 isprovided in the tube 6 near the extremity thereof adjacent the flange 23and is adapted to be actuated by a stem 26 and disc or dial 27.Anactuating member 28 is operatively rconnected to the disc or dial 27to permit actuation of vthevalve 25 in any desired manner. A pin 29Ithat is secured to vthe stem '26 co-operates with two stop-screws 30and 31 to determine the maximum and minimum openings of the valve 25.

' Air isY supplied to the Venturi tube 6 through a valve 32 intheextremity of the tube 6 opposite to thev extremity in which the throttlevalve 25 is disposed. The valve 32 'may be vadjusted or Voperated'either automaticallyor manually in any de'sired'man-V ner. Thus, itwill be'seen ,that the Venturi tube l6 constitutes a mixing chamber towhich liquid fuel may be supplied through the channel' conduit 19 inVthe stem 10 and to which air may be supplied through lthe valve 32.

The reservoir 7 is adaptedto be supplied VIwith liquid fuel through Aan'aperture 33,

shown in Fig. 5, to which any suitable pipe or conduit may be connected.Such a pipe or conduit will Vordinarily be connected to a 'fuel pumpthatv is operated whenever the engine with which the carburetor isassociated is in operation. Such a fuel pump will take liquid fuel fromany suitable tank or reservoir, which may be disposed below the level ofthe reservoir 7 lof the carburetor if desired. An aperture 34, whichalso connects with the interior of the reservoir 7, constitutes anoverflow conduit for said reservoir and is adapted to be connected bymeans of a pipe or conduit 35 tothe main fuel reservoir to permitdrainage of excess fuel from vthe carburetor reservoir to the mainreservoir. The cross-sectional area of the overflow conduit 35 is ofsuch size as to limit the amount of fuel that may be contained withinthe reservoir 7 to the level 'at which the aperture 34 connectstherewith, which is relatively close to the top of the reservoir. Twoapertures `36 and 37 of relatively small cross-sectional area connectthe chamber of the reservoir 7 with the aperture 34 at lower levels thanthat at which the main portion of the aperture 34 connects with thereservoir 7, for a purpose to be described hereinafter. A

A vertical rod 38 extends downwardly in close-fitting relation to anaperture 39 through the top portion 5 of the carburetor, and thence inrelatively loose-fitting relation through an aperture 40 in the float 9.

VThe lower extremity of the rod 38 is provided with a liange portion 4lof greater vdiameter than that of the aperture 40 and constitutes a stopor limit to determine the lowermost position of the float wit-hin thereservoir 7. rIhe rod 38 is provided with a plurality of indentations ornotches 42 near the upper extremity thereof and la resilient member 43is adapted toco-operate with these 'notches to maintain the rod 38 inthe position in which it is manually set. The 'resilient member 43 issecured to the top portion 5 of the carburetor by a screw 44.

It will 4be seen that the rod 38 may be manually adjusted to determinethe lowern'iost position of the float 9 as desired and that suchadjustment will be maintained by reason of the engagement between one ofthe notches 42 and the resilient member 43.

Vxlhen an internal combustion engine with which thecarburetor 'embodyingour invention is associated is to be started, such engine may be crankedautomatically in response to any desired condition and in any well knownmanner. The fuel. pump -associated with'the engine is thereupon operatedand supplies a quantity df fuel to the reservoir 7 andrsuch fuel isconducted from the bottom of the reservoir 7 Athrough the conduit 21,the passage 2O and the channel 19 to the Venturi tube 6, within whichthe pressure hasvbeen reduced Vby reason of the vcranking ofthe engine.,The float v9 will l be inits lowermost position, as determined by thevertical position of the rod 38, and the cross-sectional area of thechannel 19 Aat the point where this channel is intersected by thepassage 2O will be' relatively large.

Ico

ilo

Therefore, `a relatively large quantity of fuel is admitted to theVenturi tube 6, where it is mixed with the air admitted through thevalve32 to produce a relatively rich mixture. This mixture is suppliedto the engine through the throttle valve 25 and the engine will start tooperate as soon as coinbustion takes place therein.

As the reservoir 7 is supplied with additional fuel from the pump, thefloat 9 israised` to actuate the stein 10 upwari'lly.` The cross-sectionarea of the channel 19 at the point of intersection with the passage- Q0is thus gradually decreased to lessen the amount of fuel that issupplied to the mix* ing chamber within the tube 6. Since the rate ofair supply is unchanged, the fuel mixture is leaner, which is' thecondition desired as the temperature of theA engine increases. The rateat which the reservoir 7 is filled with fuel is determined by the sizeand position of the apertures 3G and 37 'through which fuel is permittedto drain back through the overflow conduit to the main reservoir. lt isobvious that by varying the number, size and position of the apertures36 and 37 the length of time required for the fuel pumpto lill the reservoir 7 with fuel may be adjusted to any desired value Whenthe reservoir7 isffilled with fuel after the `predetermined desired-time, the float 9and the stem 10 assume their uppermost positions as determined bytheposition of the stop member 15. Under this condition, thecross-sectional area of the channel conduit 19 at the point ofintersection with the passage 20 is decreased to itsV minimum value andthe yfuel mixture is likewise reduced to the minimum desired proportionof the amount of fuel to the amount of air admitted. to the mixingchamber within the tube 6. This minimum value may be determined byadjustment of the knob 16 in accordance with temperature conditions,quality of fuel, or any other desired conditions. p

The ratio of fuel and air to be supplied to the mixing chamber whenv theengine is started may be adjusted-by adjusting the position of the rod38. During cold weather, for example, the rod 38 may be set at thelowermost position, as shown in Fig. 4 of the'drawings, to permit thegreat est possible amount of fuel to be supplied to the mixing chamberWithin the tube 6 when the engine is started. Under other conditions,the rod 38 may be set at higher positions to decrease the area of thechannel conduit 19 at the point of intersection with the passage 20,thereby causing a leaner fuel mixture to be supplied to the engine whenthe same is started.

The modification shown in Fig. 6 of the drawings, consists in providingan adjust- `able valve member 15 for co-operating with may thus bepredetermined by adjusting the valve /lto obtain any desiredcross-section of the opening Fremthe foregoingdescription it will` beseen that we have provideill a carburetor comprising means forautomatically regirlating the ratio of air and fuel in the comu bustiblemixture supplied to an internal combustion engine. The maximum andminimum values of t iis ratio are readily adjustable indepeniilently ofeach other and the time required for "the ratio to be automaticallychanged fromv one limit to the other may also be adjusted as desired. Aninternal combustion engine equipped with a carburetor of this type maytherefore. be automatically operated under all temperature conditionsand with any available qual-` ity of fuel.

YVhile we have shownand described only one specific embodiment of ourinvention, it will be seen that various changes and modifications may bemadein the details of structure thereof without departing from thespirit and scope of our invention. Therefore, we desirepthatourinvention be limited only bythe prior art and the scope of theappended claims. 1

We claim as our invention:

1. A carburetor comprising a mixing chamber, means for conducting airand fuel thereto, a fuel reservoir containing a float, and meanscontrolled by the float for decreasing the rate of fuel supply fromr thereservoir to the mixing chamber when the amount of fuel inthe reservoiris increased.

2. A carburetor comprising a mixing chamber, means for conducting airandA fuel thereto, a fuel reservoir containing afloat, and meanscontrolled by the lioat for pei'- mitting an increase in the rate offuel supply from the reservoir to the mixing chamberwhen the amount offuelin the reservoiris decreased.

3. A carburetor comprising a` mixing chainber,ja fuel reservoircontaining a float, a fuel conduit connecting the fuel reservoir and themixingchamber, a valve in said conduit the degree of; opening of whichis decreased by upward movement of the float, and adjustable means forlimiting thermovement of the float. .Y

4f. A carburetor comprising a mixing chamber, a fuel reservoircontaining a vertically movable float, a fuel conduit con` necting thefuel reservoir and the mixing chamber, Va valve in said fuel conduit thedegree of opening of which is decreased by upward movement of said floatand adjustable means for limiting 'the upward movement of said float.

5. A carburetor comprising a mixing chamber, a fuel reservoir containinga vertically movable float, a fuel conduit connecting the fuel reservoirand the mixing chamber, a valve in said fuel conduit the degree ofopening of which is decreased by upward? movement of said float andadjustable means for determining the lowermest position of said float.

6. A carburetor comprising a mixing chamber, a fuel reservoir containinga vertically movable float, a fuel conduitconnecting the fuel reservoirand the mixing chamber, a valve in said fuel conduit the degree ofopening of which is decreased by upward movement of said iioat,adjustable means for limiting the upward movement of said float, andadjustable means for determining the lowermost position of said float.

7. Av carburetor comprising a vmixing chamber, a fuel reservoir beneathsaid mixing chamber, a vertically movable float in said fuel reservoir,a fuel conduit connecting said fuel reservoir and said mixing chamberand having a vertical portion, a vertical stem for the float extendingupwardly through the vertical portion of the fuel conduit and throughthe mixing chamber and having a channel of varying crosssection thereinto control the rate of fuel iow through the fuel conduit in accordancewith the position of the float, and an adjustable stop member in theupper wall of the mixing chamber' for engaging the upper extremity ofthe float stem to limit the upward movement of the float.

8. A carburetor comprising a mixing chamber, a fuel reservoir beneathsaid mixing chamber,` a vertically movable float in said fuel reservoir,a fuel conduit connecting said fuelV reservoir and said mixing chamberand having a vertical portion, a vertical stem for the float extendingupwardly through the vertical portion of the fuel conduit and throughthe mixing chamber and having a channel of varying cresssection thereinto control the rate of fuel How through the fuel conduit in accordancewith the position of the float, and a screw-threaded'member co-operatingwith a screw-threaded opening in the upper wall of the mixing chamberfor engaging the upper extremity of the float stem to limit the upwardmovement of the float.

9. A carburetor comprising areservoir member of cup form, a cover membertherefor having a substantially horizontal hollow cylindrical portionforming a mixing chamber, said cylindrical portion having a verticalrpassageway and an inclined'intersecting passageway in the lower lwallthereof, a vertical stem extending through said vertical passageway, a'iioat disposed within the reservoir member and secured to the stem, anda conduit secured to the cover member in connection with the inclinedpassageway therein, extending downwardly through an aperture in thefloatand opening into the reservoir chamber near the bottom thereof.

10. A carburetor comprising a reservoir member of cup ferm, a covermember therefor having a substantially horizontal hollow cylindricalportion forminga mixing chamn ber, said cylindrical portion having avertical passageway andan inclined intersecting passageway in the lowerwall thereof, a vertical stem extending through said verticalpassageway, said stem having a channel of varying cross-section thereinin register with the inclined passageway to form conduit extending intothe mixing chamber', a float disposed wit-hin the reservoirv member andsecured to the stem, and a conduit secured to the cover member inconnection with the inclined passageway therein, extending downwardlythrough an aperture in the float and opening into the reservoir chambernear the bottom thereof. Y

11. The method of regulating the ratio of fuel and air to be mixed in acarburetor which consists in decreasing the rate of fuel supply to themixing chamber when the amount of fuel in the float chamber isincreased.

12. n a carburetor, the combination with a mixing chamber, a reservoiradaptedto be filled with fuel and containing a float, and means forsupplying fuel to the reservoir, of means controlled by the fioat fordecreasing the rate of iow of fuel from the reservoir to the mixingchamber as the amount of fuel in the reservoir is increased, and meansfor controlling the length of time required to fill the reservoir withfuel.

13. In a carburetor, the combination with a mixing chamber, a reservoiradapted to be filledk with fuel and containing a Heat, and means forsupplying fuel to the reservoir, of means controlled by the float forregulating the rate of flow of fuel from the reservoir to the mixingchamber and means comprising an overflow conduit for controlling thelength of time required to fill the reservoir with fuel.

111-. In a carburetor, the combination with a mixing chamber, areservoir adapted to be filled with fuel and containing a Heat, andmeans for supplying fuel to the reservoir, of means controlled by thefloat for regulating the rate of flow of fuel from the reservoir to themixing chamber and an overflow conduit having an opening into thereservoir to limit the amount of fuel that may be contained by thereservoir and another opening into the reservoir to control the lengthof time required to lill the reservoir with fuel up to said limit.

15. In a carburetor, the combination with a mixing chamber, a reservoiradapted to be filled with fuel and containing a float, and

means :for supplying 'fuel to the reservoir, of means controlled by thefloat for regulating the rate of flow of fuel from the reservoir tothemxng chamber and en overflow conduit having e relatively largeopening into the reservoir neer the top thereoI to limit themnount offuel that may be Contained by the reeervor and having a pluralty ofrelatively Smell openings into the reservoir below the level of seidrelatively large opening to control the length of time required to fillthe reservoir with fuel up to the level of said relatively largeopening.

In Witness whereof We have hereunto sub- 5 scribe/flour names. v

'VELLB Y ALLEN BRACKETT. WILLIAM EDARD RICHARD.

